Making up 50mm floor height

Discussion in 'Builders' Talk' started by PEAENJAY, Oct 11, 2018.


    PEAENJAY Member

    I have a bungalow extension about to start. Two rooms will be knocked together as part of the extension work. Checking floor levels has revealed a 50mm lower floor level that will need to be brought up to the new level. The floor area is the entry hall, small study and dining room in total about 20 square meters, and will be finished with engineered wood flooring. What is the best way of making up 50mm ? the builder has suggested a 50mm screed, but I would like to take the opportunity to add insulation.
  2. Greentram

    Greentram Member

    Assuming it's pretty level, I'd make it a floating floor, say 38mm polystyrene, 1000g polythene, ply sheets, then your engineered floor to finish.

    PEAENJAY Member

    Not sure I understand your comment - if I use 38mm polystyrene where does the remaining 12mm come from ? Who makes 38mm polystyrene ? I have seen 25 & 50mm.
  4. Pollowick

    Pollowick Well-Known Member

    How will the engineered floor be fixed? Glue, nailn floating? You may find that cross battening with suitable timber and then insulate between may be the best way.
  5. ajohn

    ajohn Active Member

    I'm not a builder but I believe an insulating board is available for use under a floor then screed etc on top. Maybe a self leveller. Some googling on building regs and floors might come up with a name for what this board is called. I'd assume you could use several layers if needed.

    We knocked out a wall and was left with floor level problems and slopes which aren't a good idea when a fitted kitchen is going in. I use a Bostic self levelling compound - ultra hard. These don't really self level without help. 50mm is about it's limit but it would be very costly to do a significant area at that depth. Taking out around 10mm plus some out of level areas costed the best part of £200 even bought from a place that didn't inflate the price. I used this one because it's a rather old concrete floor and may not have a dp membrane. We've never had a damp problem but this particular leveller is suitable for semi exterior use. Many aren't.

  6. jimoz

    jimoz Active Member

    Can float a chipboard floor on pir if this is suitable for underneath your engineered floor. If the existing is nice and flat so boards aren't rocking then I'd go appropriate thickness pir insu, 18/22mm chipboard to make up your level

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